For several years, the loss of living coral habitat by coral bleaching has become a global concern, prompting researchers and scientists to study the health of coral reefs around the world. One location for this phenomenon is the southern Seychelles, in the mid-western Indian Ocean, and north of Madagascar.
Coral bleaching and rising ocean temperatures have caused 40% to 50% of corals in this region to become colorless and vulnerable to various environmental stressors. To better understand the effects of rising water temperatures on coral ecosystems, researchers used HOBO® water temperature loggers U22-001, UA-002-64, UA-002-08, UA-001-64, UA-001 -08, UTBI-001 as part of a long-term monitoring program.
"Coral reefs are one of the most productive ecosystems in the world, equal to tropical rainforests, and in many ways they are a very important component of marine ecosystems," explains Ray Bacquelia, the lead researcher for the Ocean Project (AMP). "When you have an impact on coral bleaching, it has a major impact on local and regional ecosystems."
"The main focus of our research is the sub-atoll because it is a large remote coral reef ecosystem that has been little affected by human habitation. It is the last natural laboratory on Earth. What happens is nature really responds to environmental impacts. "
To monitor water temperature, Buckley and the security team strategically placed HOBO support data loggers at several locations in the sub-atoll, Assomption, Astove, and east of St. Pierre. Each water temperature logger U22-001, UA-002-64, UA-002-08, UA-001-64, UA-001-08, UTBI-001 uses cable deployment ties and stakes, and water temperature measurement every 30 minutes to an hour.
"Water temperature loggers U22-001, UA-002-64, UA-002-08, UA-001-64, UA-001-08, UTBI-001 have become coralline algae bordered on reefs two years later, still being able to collect accurate temperature data," Buckley said.
Water temperature loggers U22-001, UA-002-64, UA-002-08, UA-001-64, UA-001-08, UTBI-001 provide ±0.2°C over a wide temperature range and accuracy provides 42000- Measure storage capacity to make it suitable for long-term deployment.
Data from the logger can be directly and quickly offloaded to a laptop via a USB based optical download base BASE-U-4 (recommended model), BASE-U-1, providing high speed, reliable data will be in wet environments. Its broken optical design does not require mechanical connectors found in many traditional underwater water temperature loggers U22-001, UA-002-64, UA-002-08, UA-001-64, UA-001-08, UTBI-001 product.
Data Analysis Using HOBOware® Occupational Graphing and Analysis Software, the collected data was easily converted into easy-to-understand graphs revealing peak and falling water temperatures over a 12-month period.
"Most coral bleaching research occurs in places where there has been a significant impact on corals due to human development," Buckley said. "While the importance of these studies to better understand coral reef health goes without saying, they fail to provide a good baseline of how an ecosystem responds in the absence of human impact. Subatolls are as close to pristine as we can get, and allow us to see coral and how fish respond to rising temperatures without outside interference."
The researchers found that where coral reef ecosystems are affected by human development, there is often a shift in the main components of the algal ecosystem from living coral to algae.
"Then the fish population switches to predominant herbivores and the algae covers the dead coral making it harder for the coral to recover. This leads to a major shift in the reef ecosystem," Buckley said.
Buckley said that over the past 10 years there has been no substantial change in fish populations in the sub-atolls, and there is essentially no human habitat.
"Coral bleaching events that did not lead to algae-dominated ecosystems were not catastrophic for fish in this area. Fish were able to adapt to the rapid loss of major live coral habitats and develop new coral habitats. We found that if no other variables affected the ecology system, fish can respond positively to these habitat changes, even as the system matrix changes."
